Branched poly(trimethylene ether) polyols

ABSTRACT

Disclosed is branched poly(trimethylene ether) polyols prepared from the acid catalyzed polycondensation reaction of 1,3-propanediol, and at least one triol comonomer selected from 1,1,1-tris(hydroxymethyl)ethane and 1,1,1-tris(hydroxymethyl)propane. Also disclosed is a branched poly(trimethylene ether) polyol with an equivalent hydroxyl functionality of about 2.1 to about 3.2 and a M n  of about 200 to about 6000. The polyols are useful in the preparation of polyurethane rigid and flexible foams.

This application claims the benefit of U.S. Provisional Application No.61/415,388, filed Nov. 19, 2010.

FIELD OF THE INVENTION

The present invention relates to branched poly(trimethylene ether)polyols and to compositions comprising the branched poly(trimethyleneether) polyols. The poly(trimethylene ether) polyols are suitable foruse in polyurethane foams.

BACKGROUND

Commercially-available polyurethane foams, elastomers and aqueouspolyurethane dispersions currently are generally produced usingpolyether diols, polyols derived from polymerization of ethylene oxideand propylene oxide, polyester polyols, vegetable oil-based polyols, andblends of two or more thereof. The majority of the polyurethanes areprepared from petroleum based feedstocks. While the polyurethane foamsprepared using these raw materials exhibit useful properties, theysuffer from the fact that the starting materials are petroleum based andnot available from renewable sources.

U.S. Pat. No. 6,946,539, US2007/0129524A1, US2009/0124719A1, andUS2008/0039582A1, disclose polyurethanes prepared using apoly(trimethylene ether) glycol. Poly(trimethylene ether)glycol (PO3G)is readily prepared by polycondensation of 1,3-propanediol (andoptionally other glycols such as ethylene glycol) which, as previouslydisclosed in U.S. Pat. No. 5,633,362, U.S. Pat. No. 5,686,276 and U.S.Pat. No. 5,821,092, can be prepared by a fermentation process using arenewable biological source. The disclosed renewably sourced PO3Gpolymers are linear polyether glycols having a number average hydroxylfunctionality of about 2 or slightly less than 2 due to the presence oflow unsaturated end groups. The lack of high hydroxyl functionalityrenders the renewable sourced poly(trimethylene ether)glycols of limiteduse in polyurethane foams.

Natural oil polyols (NOPs) having high hydroxyl functionality have beenused to replace petrochemical based polyols in production ofpolyurethane rigid and flexible foams. However, making flexiblepolyurethane foams from the NOPs having a renewable content more thanabout 50%, and less than about 50% petroleum based content, and havingdesirable performance characteristics can be challenging because oftheir chemistry and properties relative to conventional polyetherpolyols. For example, NOPs generally have less-reactive stericallyhindered secondary hydroxyl groups, unsaturation, greater hydrophobicityas compared to conventional oils, and can have inconsistencies incomposition. Foams made from NOPs can be less flexible and/or lessresilient than conventional flexible polyurethane foams.

A renewably sourced polyol having hydroxyl functionality greater thantwo, with low freezing point and having a good balance betweenhydrophilic and hydrophobic character would have benefits in productionof products such as foams, polyurethane themosets, coatings, adhesivesand sealants with excellent properties, as well as many other end uses.

SUMMARY

One aspect of the invention is a branched poly(trimethylene ether)polyol comprising repeating units of Formula I, Formula II, and FormulaIII

wherein R is methyl or ethyl and Q is selected from Formula (IIIa) and(IIIb):

-   -   wherein m is 1-20 and n is 1 to 3, and further comprising end        groups of Formula IV, V, and VI:

Another aspect of the present invention is a composition comprising ablend of a branched poly(trimethylene ether) polyol comprising repeatingunits of Formula I, Formula II, and Formula III

wherein R is methyl or ethyl and Q is selected from Formula (IIIa) and(IIIb):

-   -   wherein m is 1-20 and n is 1 to 3 and further comprising end        groups of Formula IV, V, and VI:

and one or more other polyols selected from petroleum based polyols andvegetable oil based polyols.

Another aspect of the invention is a polyurethane foam comprising thebranched poly(trimethylene ether) polyol, optionally blended with one ormore other polyols selected from petroleum based polyols and vegetableoil based polyols.

In some embodiments, the branched poly(trimethylene ether) polyol isrenewably sourced.

These and other aspects of the invention will be apparent to one skilledin the art in view of the following specification and claims.

BRIEF DESCRIPTION OF THE FIGURE

FIG. 1 illustrates a comparison of the phase transitions (T_(g), T_(c),and T_(m)) from differential scanning calorimetry spectrum of thebranched poly(trimethylene ether) polyols from Examples 4 (b) and 6 (c)with the phase transitions of Cerenol® H-2000 homopolymer (a).

DETAILED DESCRIPTION

By “triol” is meant a compound containing three reactive —OH groups. Thecompound is typically an alkane of 3 to 10 carbons.

By “branched” is meant a polymer molecule that is composed of a mainchain with one or more substituent side chains or branches.

By “polyol” is meant a polymer molecule having an equivalent hydroxylfunctionality greater than 2.

By “equivalent hydroxyl functionality” is meant the average number ofhydroxyl groups per molecule of a polyol.

By “amorphous polyol” is meant a polyol that possess little or no degreeof crystallinity and a melt enthalpy less than 10 J/g as determined in asecond heat differential scanning calorimetry (DSC) spectrum.

By “semicrystalline polyol” is meant a polyol that has distinct coldcrystallization (T_(c)), melt temperature (T_(m)) peaks, and a meltenthalpy (ΔH_(m)) greater than 10 J/g as determined by a second heatdifferential scanning calorimetry (DSC) spectrum.

By “high oleic vegetable oil based polyol” is meant a polyol derivedfrom vegetable oil comprising triglycerides of fatty acids of which morethan 65 weight percent are oleic acid.

By “polyisocyanate” is meant a polyisocyanate or polyisocyanurate having2 or more than isocyanate groups.

By “polyurethane foam” is meant a rigid, flexible, or semi flexiblefoam. The flexible foam can be slabstock or molded foam.

Disclosed herein is a branched poly(trimethylene ether) polyolcomprising repeating units of Formula I, Formula II, and Formula III:

wherein R is methyl or ethyl and Q is selected from Formula (IIIa) and(IIIb):

wherein m is 1-20 and n is 1 to 3. The polyol further comprises endgroups of Formula IV, V, and VI:

In some embodiments, Q of both Formula (IIIa) and Formula (IIIb) arepresent.

The branched poly(trimethylene ether) polyols are suitable for use inpolyurethane foams.

In some embodiments, the poly(trimethylene ether) polyols are renewablysourced, and in further embodiments they can be used in blendcompositions with natural oil based polyols. Renewably sourced branchedpoly(trimethylene ether) polyols, optionally blended with vegetable oilbased polyols, can be used as an alternative to petroleum based polyolsin polyurethane foams.

In some preferred embodiments, the branched poly(trimethylene ether)polyol is amorphous.

The branched poly(trimethylene ether) polyols preferably have a M_(n) ofabout 200 to about 6000.

The branched poly(trimethylene ether) polyols disclosed herein cancomprise primary hydroxyl groups present both as pendant CH₂OH groupsand chain end CH₂OH groups and do not contain secondary hydroxyl groups.The primary hydroxyl groups are located randomly on main and branchedchains of a molecule as well as at the chain ends. The absence ofsecondary hydroxyl end groups and steric hindered hydroxyl groups on themain polymeric chain or a side chain makes these poly(trimethyleneether) polyols more reactive towards polyisocyanates, carboxylic acidsand their esters than many conventional polyols containing secondaryhydroxyl groups.

The branched poly(trimethylene ether) polyols can be made from thepolycondensation reaction of 1,3-propanediol and at least one triolcomonomer selected from 1,1,1-tris(hydroxymethyl)ethane and1,1,1-tris(hydroxymethyl)propane. The 1,3-propanediol can be1,3-propanediol alone or dimer or trimer of 1,3-propanediol, andmixtures thereof.

In one embodiment, the triol comonomer is1,1,1-tris(hydroxymethyl)ethane and in another embodiment the triolcomonomer is 1,1,1-tris(hydroxymethyl)propane.

When a triol comonomer is incorporated into the polymer during thepolycondensation process, the resulting branched poly(trimethyleneether) polyol is a random polymer having at least one branch in amolecule, as characterized by proton NMR. As the amount of the triolcomonomer in the polymer increases the degree of branching increases,and higher amounts of comonomer can lead to crosslinked polyol which isundesirable.

In one embodiment, the branched poly(trimethylene ether) polyolcomprises from about 90 to about 99 mole % 1,3-propanediol and fromabout 1 to about 10 mole % triol comonomer. In one embodiment thebranched poly(trimethylene ether) polyol comprises from about 2 to about8 mole % triol comonomer.

In another embodiment, the branched poly(trimethylene ether) polyolcomprises from about 90 to about 99 mole % 1,3-propanediol and fromabout 1 to about 10 mole % 1,1,1-tris(hydroxymethyl)ethane comonomer. Inanother embodiment the branched poly(trimethylene ether) polyolcomprises from about 90 to about 99 mole % 1,3-propanediol and fromabout 1 to about 10 mole % 1,1,1-tris(hydroxymethyl)propane comonomer.

In one embodiment, the branched poly(trimethylene ether) polyolcomprises about 90 to about 99 mole % repeating units of Formula I andabout 1 to about 10 mole % repeating units of one or both of Formula IIand Formula III. In one embodiment the branched poly(trimethylene ether)polyol comprises about 2 to about 8 mole % repeating units of one orboth of Formula II and Formula III.

When the repeating units of one or both of Formula II and Formula IIIwhere R is methyl are present at higher than about 2.5 mole percent thebranched poly(trimethylene ether) polyol is an amorphous liquid polymer.In some embodiments, the repeating units of Formula II and/or FormulaIII are present in amounts of about 2.8 mole percent or higher, or about3.2 mole percent or higher,

The degree of the crystallinity of the poly(trimethylene ether) polyolsdisclosed herein depends on several factors that include type and amountof comonomer in the backbone, number of branches, and the length ofbranched and main chains. Linear poly(trimethylene ether)glycolhomopolymers prepared from polycondensation of 1,3-propanediol aresemicrystalline polymers having a distinct cold crystallizationtemperature (T_(c)) peak at about −37° C., melt temperature (T_(m))peaks in the range of 5-20° C. depending on the molecular weight, and aenthalpy of melting (ΔH_(m)) of about 80-95 J/g.

In contrast to linear poly(trimethylene ether)glycol homopolymers, thepoly(trimethylene ether) polyols disclosed herein are preferablyamorphous in nature. The poly(trimethylene ether) polyol does notexhibit a T_(c) or T_(m) when the triol comonomer,1,1,1-tris(hydroxymethyl)ethane, is incorporated into the backbone atabout 2.8 mol % and higher.

The functionality and functionality distribution are useful parametersto characterize the composition of polyols. The branchedpoly(trimethylene ether) polyol prepared from polycondensation is amixture of molecules having from about 2 to about 5 hydroxyl groups permolecule, and the number of hydroxyl groups in a polyol molecule dependsupon the type and amount of comonomer and manufacturing polycondensationprocess. The physical properties therefore can be controlled by varyingthe composition.

One practical method for functionality determination is based on theassessment of the number average molecular weight (M_(n)) of thebranched poly(trimethylene ether) polyol by gel permeationchromatography together with hydroxyl number determination fromtitration. The hydroxyl functionality (f) is calculated by using theequation:f=M _(n)×OH#/56100where M_(n) is the number average molecular weight and OH# is the totalhydroxyl number determined by titration, 56100 is a constant related toKOH.

Alternatively, the equivalent hydroxyl functionality, fe, of the mixturecan be calculated using the following equation:

${fe} = \frac{{Total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{hydroxyl}\mspace{14mu}{groups}}{{Total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{molecules}}$

The branched poly(trimethylene ether) polyols disclosed herein typicallyhave hydroxyl numbers in the range of 550 to 65 mg KOH/g, the equivalenthydroxyl functionality ranging from about 2.1 to about 3.2 and thenumber average molecular weight (M_(n)) is from about 200 to about 6000,or from about 250 to about 5000, or from about 1000 to about 2500.

Typically the branched poly(trimethylene ether) polyols disclosed hereinhave a polydispersity index or molecular weight distribution (MWD)within the range of 1.5 to 2.8. The polyol may have residual unreacteddiol and triol monomers and are part of the MWD.

The branched poly(trimethylene ether) polyols disclosed herein haveviscosities in the range from about 50 to 5000 cPs at 40° C. In general,the viscosity of the branched poly(trimethylene ether) polyol increaseswith increase in molecular weight and also with increase in hydroxylfunctionality.

The branched poly(trimethylene ether) polyols have typically an APHAcolor of less than 300, more typically less than 200, and most typicallyless than 100. The color of the polyols can be further improved, ifdesired, by the addition of a color-reducing aid such as activatedcarbon black. One suitable method is disclosed in U.S. PatentApplication No. 2004/022516, filed Aug. 5, 2003.

The surface tension of the branched poly(trimethylene ether) polyolsdisclosed herein is about 40 to about 42 dynes/cm. The surface tensionis a measure of the inward force acting on the surface of a liquid dueto the attraction of molecules in the liquid. In general, high levels ofintermolecular forces among the molecules in a liquid have high valuesof surface tension.

The more hydroxyl functional groups in the molecule of the branchedpoly(trimethylene ether) polyol in general, the higher thehydrophilicity of the polyol and thereby the greater the degree ofintermolecular interactions and viscosity; however the presence ofmethyl or ethyl pendent groups in the molecule can decrease itshydrophilicity. The measured surface tensions of the branchedpoly(trimethylene ether) polyols are very close to that of homopolymersof linear poly(trimethylene ether)glycol, which indicates that thehydrophilicity of the poly(trimethylene ether) polyol is similar to thatof the homopolymers in spite of higher hydroxyl functionality.

The branched copolyether poly(trimethylene ether) polyols disclosedherein also have relatively few unsaturation (allyl) end groups,typically less than 30 meq/kg, more typically less than 25 meq/kg.Unsaturation end groups in polyol can act as chain terminating agents inpolyurethane chemistry and can limit the molecular weight of thepolyurethane and thereby affect the physical properties. In contrast topoly(trimethylene ether) glycol homopolymers with hydroxyl functionalityof less than 2, the impact of low unsaturation end groups in thebranched poly(trimethylene ether) polyol on properties of polyurethaneis less significant because the average hydroxyl functionality isgreater than 2.

The conventional additives commonly used in polyether polyols can beadded to the branched poly(trimethylene ether) polyols. Such additivesinclude delusterants (e.g., TiO₂, zinc sulfide or zinc oxide), colorants(e.g., dyes), stabilizers (e.g., antioxidants, ultraviolet lightstabilizers, heat stabilizers) fillers, flame retardants, pigments,antimicrobial agents, antistatic agents, optical brighteners, extenders,processing aids, viscosity boosters, and other functional additives. Asa specific example, an antioxidant prevents oxidation of polyethers thatare subject to oxidation during storage. Preferred antioxidantstabilizers are butylated hydroxy toluene (BHT) and Vitamin E, used in aquantity of about 50 to about 5000 micrograms/g based on the weight ofthe polymer. Preferably, the amount of antioxidant is from about 100 toabout 200 micrograms/g.

The process of making the branched poly(trimethylene ether) polyolsdisclosed herein can be a batch, semi-continuous, or continuous. Thetriol comonomer can be added prior to or during initial polymerizationof 1,3-propanediol. Suitable processes include those disclosed in U.S.Pat. Nos. 6,720,459 and 6,977,291, with further reaction of desiredcomonomer with the 1,3-propanediol reactant.

The 1,3-propanediol can be obtained by any of the various well knownchemical routes or by biochemical transformation routes. In somepreferred embodiments, the 1,3-propanediol is obtained biochemicallyfrom a renewable source (“biologically-derived” 1,3-propanediol).

A particularly preferred source of 1,3-propanediol is via a fermentationprocess using a renewable biological source. As an illustrative exampleof a starting material from a renewable source, biochemical routes to1,3-propanediol have been disclosed that utilize feedstocks producedfrom biological and renewable resources such as corn feed stock. Forexample, bacterial strains able to convert glycerol into 1,3-propanediolare found in the species Klebsiella, Citrobacter, Clostridium, andLactobacillus. The technique is disclosed in several patents, includingU.S. Pat. No. 5,633,362, U.S. Pat. No. 5,686,276 and U.S. Pat. No.5,821,092. For example, U.S. Pat. No. 5,821,092 discloses, inter alia, aprocess for the biological production of 1,3-propanediol from glycerolusing recombinant organisms. The process incorporates E. coli bacteria,transformed with a heterologous pdu diol dehydratase gene, havingspecificity for 1,2-propanediol. The transformed E. coli is grown in thepresence of glycerol as a carbon source and 1,3-propanediol is isolatedfrom the growth media. Since both bacteria and yeasts can convertglucose (e.g., corn sugar) or other carbohydrates to glycerol, theprocesses disclosed in these publications provide a rapid, inexpensiveand environmentally responsible source of 1,3-propanediol monomer.

The biologically-derived 1,3-propanediol, such as produced by theprocesses disclosed and referenced above, contains carbon from theatmospheric carbon dioxide incorporated by plants, which compose thefeedstock for the production of the 1,3-propanediol. In this way, thebiologically-derived 1,3-propanediol contains only renewable carbon, andnot fossil fuel-based or petroleum-based carbon. The branchedpoly(trimethylene ether) polyols made from the biologically-derived1,3-propanediol, therefore, may have less impact on the environment asthe 1,3-propanediol used in the compositions does not depletediminishing fossil fuels and, upon degradation, releases carbon back tothe atmosphere for use by plants once again. Thus, the compositionsdisclosed herein can be characterized as more natural and having lessenvironmental impact than similar compositions comprising petroleumbased polyols.

Biologically-derived 1,3-propanediol, and compositions comprisingbiologically-derived 1,3-propanediol, therefore, may be distinguishedfrom their petrochemical derived counterparts on the basis of ¹⁴C(f_(M)) and dual carbon-isotopic fingerprinting, indicating newcompositions of matter. The ability to distinguish these products isbeneficial in tracking these materials in commerce. For example,products comprising both “new” and “old” carbon isotope profiles may bedistinguished from products made only of “old” materials. Hence, theinstant materials may be followed in commerce on the basis of theirunique profile and for the purposes of defining competition, fordetermining shelf life, and especially for assessing environmentalimpact.

Preferably the 1,3-propanediol used as the reactant or as a component ofthe reactant will have a purity of greater than about 99%, and morepreferably greater than about 99.9%, by weight as determined by gaschromatographic analysis. Particularly preferred are the purified1,3-propanediols as disclosed in US20040260125A1, US20040225161A1 andUS20050069997A1, and poly(trimethylene ether) glycol made therefrom asdisclosed in U.S. Pat. No. 7,323,539.

The renewable sourced carbon content of the branched poly(trimethyleneether) polyol is greater than 70%, typically greater than 80% and moretypically greater than 90% by weight of the total carbon content. Thebio based carbon content is either calculated based on number of carbonsor determined according to ASTM-D6866.

The renewably sourced branched poly(trimethylene ether) polyols can beused to replace completely or partially one or more petroleum basedpolyols that are being used to make end products such as polyurethanefoams and elastomers. The renewably sourced branched poly(trimethyleneether) polyols can also be blended with petroleum-based polyols and/ornatural oil based polyols. “Natural oils” is used herein to refer tonon-petroleum based, naturally occurring oils.

The branched poly(trimethylene ether) polyols can blended with one ormore polyols derived from natural oils, such as, for example example,the polyols derived from natural oils including vegetable oil basedpolyols selected from soybean oil, palm based oils, sunflower oil,safflower oil, corn oil, canola oil, sesame oil, linseed oil, olive oil,cottonseed oil, castor oil and combinations thereof. Renewably sourcedpoly(trimethylene ether) polyols may be preferred for such blends. Thevegetable oils can be natural or genetically modified vegetable oils,for example, high oleic soybean oil, high oleic sunflower oil, higholeic safflower oil, high oleic peanut oil. “High oleic” is used in theart to refer to oils having 65% or more oleic content. Other than castoroil, which has hydroxyl groups, all other vegetable oils need to beconverted into polyols by chemical modifications. Although there areseveral known methods in the literature to make polyols from vegetableoils, a typical method comprises two steps: (i) partial or completeepoxidation of oils with peroxyacid that converts a portion or all ofthe double bonds of the oil to epoxide groups, (ii) ring opening with analcohol in the presence of a catalyst that converts a portion or all ofthe epoxide groups into hydroxyl groups. U.S. Pat. No. 7,691,914discloses one method of making polyols from vegetable oils.

The polyols derived from genetically modified high oleic vegetable oilare preferred over natural oil based polyols with low levels of oleicacid. In particular, genetically modified high oleic soybean oil is morehomogenous in composition than commodity soybean oil, due to itsrelatively high concentrations of monounsaturated oleic acid (greaterthan 65%) and relatively low levels of polyunsaturated linoleic andlinolenic acids (less than 20%). In addition to the mono andpolyunsaturated fatty acids, the vegetable oils can contain saturatedfatty acids. The amount of unsaturation in vegetable oils can bequantified by iodine value and typically the iodine values for thevegetable oils will range from about 40 to 240. For example, commoditysoybean oil has an iodine value of about 120-140 which corresponds to4.6 double bonds per molecule, whereas genetically modified soybean oilhas an iodine value less than 90. U.S. Pat. No. 5,981,781 discloses aprocess of making high oleic soybean oil.

A preferred polyol blend comprises a branched poly(trimethylene ether)polyol and a polyol derived from genetically modified high oleic soybeanoil. The amount of branched poly(trimethylene ether) polyol in the blendcan range from about 1 to about 99% by weight of the total weight of theblend. In some embodiments, the amount of branched polyol is from about10 to about 90% by weight of the total weight of the blend, or about 20to about 80% by weight of the total weight of the blend.

The branched poly(trimethylene ether) polyols or the branchedpoly(trimethylene ether) polyol blends with polyols derived fromvegetable oils disclosed herein have a wide variety of end useapplications. One application is in the manufacture of polyurethanes forCASE (coatings, adhesives, sealant and elastomer) and foam applications.For rigid polyurethane foam applications, short chain polyols with highhydroxyl number and high functionality are preferred. For flexibleslabstock or molded polyurethane foam applications, long chain polyolswith lower hydroxyl number and functionality are preferred. Theproduction and applications of polyurethanes are well known in the art.See Ulrich, H. 2001, Polyurethanes, Encyclopedia of Polymer Science andTechnology, John Wiley & Sons, Inc.

The expression “polyurethane foam” as used herein refers to closedcellular or open cellular products as obtained by reacting di- orpolyisocyanates with isocyanate-reactive hydrogen containing compoundssuch as polyols, aminoalcohols and/or polyamines, using blowing agents,such as fluorocarbons, fluoroolefins, hydrocarbons, chlorocarbons,acetone, methyl formate, and CO₂ generated in situ by reaction of thepolyisocyanate with water added to the formulation.

The slabstock or molded polyurethane foams comprise the reaction productof ingredients comprising: (a) an isocyanate-reactive compoundcomprising a branched poly(trimethylene ether) polyol having equivalenthydroxyl functionality from about 2.4 to about 3.2 or anisocyanate-reactive compound comprising a polyol blend of from about 1to about 99% by weight of the branched poly(trimethylene ether) polyoland from about 99 to about 1% by weight of vegetable oil based polyol;(b) a polyisocyanate component comprising a di or polyisocyanate and (c)a blowing agent. In some preferred embodiments, the vegetable oil basedpolyol is the high oleic soybean oil based polyol.

The branched poly(trimethylene ether) polyols disclosed herein have manyuseful properties when used alone or blended with other polyols inmaking polyurethane foams. The useful properties of the polyol includehigh hydroxyl functionality, reactive primary hydroxyl groups, low glasstransition temperature, low freezing point (liquid with no or littledegree of crystallinity), low viscosity, good hydrophilic andhydrophobic balance, high renewable content, no odor, low acid numberand low color. They offer flexibility, resilience and hydrolyticstability to the foams.

EXAMPLES Characterization

Using the NMR method, the number average molecular weight and the numberaverage functionality of the branched poly(trimethylene ether)poly(trimethylene ether) polyol were calculated.

¹H NMR spectrum (CDCl₃ and trifluoroacetic anhydride solvents) of thecopolymer had the following main chemical shifts: δ=0.94, 1.00, 1.008(s, CH₃—C(CH₂O)₃), 1.89, 1.93, 2.01 (t, —O—CH₂—CH₂—CH₂—O, backbone),3.30 to 3.58 (t, CH₂—O—CH₂— backbone), 4.3-4.4 (t, HO—CH₂—C(CH₃)), 4.46(HO—CH₂)

Proton NMR distinguishes the protons corresponding to the end groups(CH₂—OH), middle ether groups (CH₂—O—CH₂), methyl groups of co-monomerwith varying functionality (CH₃—C(CH₂O)₃). As the branched1,1,1-tris(hydroxymethyl)ethane with three reacted hydroxyls do not haveend groups, methyl groups of 1,1,1 tris(hydroxymethyl)ethane were usedfor calculating molecular weight and functionality contribution from1,1,1-tris(hydroxymethyl)ethane. Methyl group carbons have threehydrogens and the carbon atoms of end groups and ether linkages have twohydrogens. Hence, the response area of methyl groups needs to bemultiplied with ⅔ to equalize.

The number average molecular weight (M_(n)) of the branchedpoly(trimethylene ether) polyol was calculated using the followingequation:

M_(n) = (DP * mole  %  PDO * 58)/100 + (DP * mole  %  TME * 102)/100 + 18 − unsat  ends/mole * 18${DP} = {\frac{{{Total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{ether}\mspace{14mu}{linkages}} + {{unsaturated}\mspace{14mu}{end}\mspace{14mu}{groups}}}{{{PDO}\mspace{14mu}{ends}} + {{unsaturated}\mspace{14mu}{ends}} + {{TME}\mspace{14mu}{ends}} - {{branched}\mspace{14mu}{TME}}} + 1}$$\mspace{20mu}{{DP} = {\frac{e + u}{h + u + m - t} + 1}}$and the equivalent hydroxyl functionality, or functionality, wascalculated as shown below, using the following abbreviations:

-   DP Degree of polymerization-   TME 1,1,1 Tris(hydroxymethyl)ethane-   u Unsaturated ends per polymer molecule-   e Area of total ether linkages-   h Area of PDO end groups-   m, d, t ⅔ of the areas of 1,1,1-tris(hydroxymethyl)ethane methyl    groups with mono, di and tri ether linkages, respectively.

${Functionality} = \frac{{Total}\mspace{14mu}{number}\mspace{14mu}{hydroxyl}\mspace{14mu}{end}\mspace{14mu}{groups}}{{Total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{molecules}}$${Functionality} = \frac{{2m} + d + h}{{\left( {e + h + u + m - t} \right)/2}{DP}}$

Polydispersity Index (M_(w)/M_(n)) of the polyols was measured by gelpermeation chromatography (GPC). The GPC instrument was calibrated usinglinear poly(trimethylene ether) glycol homopolymer. ASTM method D445-83and ASTM method D792-91 were used to determine the absolute (dynamic)viscosity and density of the polymer, respectively. The color of polyolswas measured using Hunter Lab Color Quest colorimeter and expressed asAPHA index. The phase transitions such as melting, crystallization andglass transition temperatures of the polyols were obtained fromdifferential scanning calorimetry (DSC). Surface tension was measuredfor the polyols by ring (DuNouy) method using Cahn dynamic contact angleanalyzer (model DCA-312).

Example 1

450 g (5.9 moles) of 1,3 propanediol (Susterra® propanediol from DuPontTate & Lyle Bioproducts, Loudon, Tenn.), 78.9 g (0.66 moles; 10 mol %)of 1,1,1-tris(hydroxymethyl)ethane (Aldrich) and 5.34 g of H₂SO₄ (VWR,95 wt %) charged into a 1 L four-neck round bottomed flask fitted withmechanical stirrer and condenser to cool and collect byproducts. Thereactor was flushed with dry nitrogen gas to remove air. The reactionmixture was heated to 165° C. and reaction was continued for 5.5 h. Thereaction was stopped and the reaction products were allowed to cool.

The obtained product was mixed with 500 mL of water and hydrolyzed at90° C. for 2 h. The temperature was then reduced to 60° C. 500 mL of 2wt % Na₂CO₃ solution was slowly added and mixed for 30 min. The productwas transferred into separating funnel. After separation the lower partwas collected and mixed with 1 L of water and again transferred intoseparation funnel. The lower organic part was collected and dried at 90°C. using rotary evaporator. The obtained product was characterized usingNMR, GPC, DSC and wet chemical analysis. (titration and viscositymeasurement). The color of the branched polyol was low and found to be53 APHA.

Comparative Example 1

319 g (4.19 moles) of Bio-PDO™, 96.28 g (1.04 moles) of glycerol(Aldrich) and 3.75 g of H₂SO₄ (VWR, 95 wt %) was charged into 1 Lfour-neck round bottomed flask fitted with mechanical stirrer andcondenser to cool and collect byproducts. The reactor was flushed withdry nitrogen gas to remove air. The reaction mixture was heated to 166°C. and reaction was continued for 5.5 h. The heating was then stoppedand the reaction mixture was allowed to cool. The obtained product waspurified as described in Example 1.

The resulting product was dark in color which is undesirable for manyapplications.

Example 2

2700 g (35.48 moles) of 1,3-propanediol, 270 g (2.25 moles; 6 mol %) of1,1,1-tris(hydroxymethyl)ethane (Aldrich) and 30.1 g of H₂SO₄ (VWR, 95wt %) charged into 5 L four-neck round bottomed flask fitted withmechanical stirrer and condenser to cool and collect byproducts. Thereactor was flushed with dry nitrogen gas to remove air. The reactionmixture was heated to 166° C. and reaction was continued for 14 h. Theheating was then stopped and the reaction product was allowed to cool.

The obtained product was neutralized with 68 g sodium carbonate solution(68 g in 120 mL of deionized water) at 120° C. for 6 h. The product wasfiltered using solka-floc filter aid. The product was characterized asdisclosed in Example 1.

Example 3

2733 g (35.9 moles) of 1,3-propanediol, 120 g (1 mole; 2.7 mol %) of1,1,1-tris(hydroxymethyl)ethane (Aldrich), 25.87 g of H₂SO₄ (VWR, 95 wt%) and 2.54 g of sodium carbonate dissolved in 10.5 mL water was addedcharged into 5 L four-neck round bottomed flask fitted with mechanicalstirrer and condenser to cool and collect byproducts. The reactor wasflushed with dry nitrogen gas to remove air. The reaction mixture washeated to 166° C. and reaction was continued for 21 h 15 min. Theheating was then stopped and the reaction product was allowed to cool.

The obtained product was mixed with 1.5 L of water and hydrolyzed at 95°C. for 4 h. Then 330 mL of 10 wt % Na₂CO₃ solution was slowly added andmixed for 30 min. The product was distilled under reduced pressure toremove water and filtered using solka-floc filter aid. The product wascharacterized using ¹H NMR.

Example 4

2433 g (32 moles) of 1,3-propanediol, 120 g (1 mole; 3 mol %) of1,1,1-tris(hydroxymethyl)ethane (Aldrich), 25.37 g of H₂SO₄ (VWR, 95 wt%) and 2.54 g of sodium carbonate dissolved in 10.5 mL water was addedcharged into 5 L four-neck round bottomed flask fitted with mechanicalstirrer and condenser to cool and collect byproducts. The reactor wasflushed with dry nitrogen gas to remove air. The reaction mixture washeated to 166° C. and reaction was continued for 21 h 45 min. Theheating was then stopped and the reaction product was allowed to cool.

The obtained product was mixed with 1.5 L of water and hydrolyzed at 95°C. for 4 h. Then 330 mL of 10 wt % Na₂CO₃ solution was slowly added andmixed for 30 min. The product was distilled under reduced pressure toremove water and filtered using solka-floc filter aid. The product wascharacterized using ¹H NMR. The color of the polyol was found to be 150APHA

Example 5

The procedure was similar to the procedure disclosed in Example 4 exceptthe sulfuric acid amount was 25.9 g and the reaction time was 22 hours.The color of the polyol was found to be 162 APHA

Table 1 below summarizes the composition and properties of the branchedpoly(trimethylene ether) polyols prepared in Examples 1-5 using protonNMR method.

TABLE 1 Average PDO MeC(CH₂OH)₃ Ex M_(n) OH # Functionality mole % mole% 1 244 522 2.3 92.5 7.5 2 982 157 2.8 94.8 5.2 3 1358 104 2.6 97.5 2.54 2137 76.5 2.9 97.2 2.8 5 2171 75.5 2.9 97.2 2.8

As shown in Table 1, it is possible to synthesize wide range of branchedpoly(trimethylene ether) polyols having different hydroxyl numbers,functionality and molecular weights by selecting the right amount of thetriol comonomer and the process conditions. The branchedpoly(trimethylene ether) polyol of example 1 is particularly suitablefor polyurethane rigid foam applications because this poly(trimethyleneether) polyol comprised of short chains with high hydroxyl numbers of atleast 250 whereas the rest of the poly(trimethylene ether) polyols aremore suitable for flexible foam applications.

Table 2 below compares the properties of the branched poly(trimethyleneether) polyols with linear homopolymers. The Comparative Examples werecommercial Cerenol® homopolymers obtained from E.I. du Pont de Nemoursand Company, Wilmington, Del.

TABLE 2 Property Units Comp. Ex 2 Comp Ex 3 Comp. Ex 4 Example 2 Example3 Example 4 Bio based % 100 100 100 91.7 95.6 95.2 carbon content Molepercent % 0 0 0 5.2 2.5 2.8 of triol in polymer Hydroxyl mg 107 79 55157 104 76 number KOH/g (titration) Average 1.98 1.98 1.97 2.82 2.59 2.9Functionality M_(n) (GPC) daltons 1094 1428 1971 1089 1497 2091Polydispersity M_(w)/M_(n) 1.63 1.73 1.79 1.85 1.92 2.20 indexUnsaturation meq/kg 14 16 16 20 21 20 (NMR) Viscosity cP @ 40° C. 247410 839 383 527 1520 @ 100° C. 36.2 60 124 45.5 73 196 Viscosity 204 225262 183 220 264 Index Density @ 40° C. g/cc 1.025 1.016 1.015 1.0281.021 1.035 Glass ° C. −77 −77 −76 −76 −76 −73 transition temperature(T_(g)) Cold ° C. −37 −38 −38 none −9 none crystallization temperature(T_(c)) Melting temp. , ° C. 8.0; 15.3 10.8; 16.1 14.4; 17.2 none 4.2;11.5 none (T_(m)) Melting J/g 83 84 93 none 13 none enthalpy Refractive1.4622 1.4625 1.4626 1.4639 1.4648 1.4650 index Surface Dynes/cm 40.140.8 40.0 41.2 40.5 40.7 tension,

The data in Table 2 demonstrates that about 2.8 mol % of triol or higherincorporation changed the crystalline polymer to amorphous polymer. Atabove 2.5 mol % of triol incorporation, the degree of crystallizationand the rate of crystallization of the poly(trimethylene ether) polyoldecreased dramatically, as evident from significantly lower meltenthalpy and higher cold crystallization temperature than thecorresponding homopolymer. The molecular weight distribution is slightlybroader and viscosity is higher for higher molecular weight branchedpolyols than that of linear polyol. The surface tension of branchedpoly(trimethylene ether) polyols are very similar to that of linearpolyols suggesting the branched polyols have similar hydrophiliccharacter of linear polyols in spite of higher hydroxyl functionality.

Example 6

2433 g (32 moles) of 1,3-propanediol, 138.5 g (1.15 mole; 3.47 mol %) of1,1,1-tris(hydroxymethyl)ethane (Aldrich), 25.8 g of H₂SO₄ (VWR, 95 wt%) and 2.7 g of sodium carbonate dissolved in 10.5 mL water was addedinto 5 L four-neck round bottomed flask fitted with a mechanical stirrerand condenser to cool and collect byproducts. The reactor was flushedwith dry nitrogen gas to remove air. The reaction mixture was heated to166° C. and reaction was continued for 21 h 45 min.

The heating was then stopped and the reaction product was allowed tocool.

The obtained product was mixed with 1.5 L of water and hydrolyzed at 95°C. for 4 h. Then 150 mL of 21.6 wt % Na₂CO₃ solution was slowly addedand mixed for 30 min. The product was distilled under reduced pressureto remove water and filtered using solka-floc filter aid. The productwas characterized using ¹H NMR, and the results are shown in Table 3below.

TABLE 3 Average PDO MeC(CH₂OH)₃ Ex M_(n) Functionality mole % mole % 61544 2.8 96.85 3.15

The melting temperature and melting enthalpy of the product from DSCanalysis were found to be 10.5° C. and 0.56 J/g respectively. The verylow melting enthalpy value indicates that the product is largelyamorphous in nature.

FIG. 1 is the DSC spectra that compares the phase transitions ofbranched poly(trimethylene ether) polyols from Example 4 (b) and Example6 (c) vs linear Cerenol® H-2000 homopolymer (a).

Example 7

2436 g (32 moles) of 1,3-propanediol, 134.2 g (1 mole; 3 mol %) of1,1,1-tris(hydroxymethyl)propane (Aldrich), 25.78 g of H₂SO₄ (VWR, 95 wt%) and 2.64 g of sodium carbonate dissolved in 15 mL water was addedinto 5 L four-neck round bottomed flask fitted with mechanical stirrerand condenser to cool and collect byproducts. The reactor was flushedwith dry nitrogen gas to remove air. The reaction mixture was heated to167° C. and reaction was continued for 21 h 45 min. The heating was thenstopped and the reaction product was allowed to cool.

The obtained product was mixed with 1.5 L of water and hydrolyzed at 95°C. for 4 h. Then 330 mL of 10 wt % Na₂CO₃ solution was slowly added andmixed for 30 min. The product was distilled under reduced pressure toremove water and was filtered using solka-floc filter aid. The numberaverage molecular weight of the polyol was found to be 2318.

Example 8

A 50/50 blend was prepared my mixing the branched poly(trimethyleneether) polyol (from Example 4) having M_(n) and a surface tension of40.7 dynes/cm with a naturally occurring polyolsuch as castor oil polyol(from Spectrum) having M_(n) of 980 daltons and a surface tension of36.0 dynes/cm. The resulting blend was homogeneous (completely miscible)and had a surface tension of 37.4 dynes/cm.

A 50/50 polyol blend by weight was prepared my mixing the branchedpoly(trimethylene ether) polyol (from Example 4) having very lowunsaturation (20 meq/kg) with a renewably sourced vegetable oil basedpolyol (Agrol® from BioBased Technologies®, LLC, Fayetteville, Ark.)having a hydroxyl functionality of 3.6 and high unsaturation (iodinevalue of about 92 cgl2/g). The resulting blend was homogeneous(completely miscible) indicating excellent compatibility ofpoly(trimethylene ether) polyol with the vegetable oil based polyol andcontain reduced levels of unsaturation and ester groups that providesbetter oxidative stability and hydrolytic stability than Agrol® polyol.

Flexible Slabstock Polyurethane Foams Example 9

The foam formulation is prepared by using the ingredients listed inTable 4 Toluene diisocyanate is added to the mixture containing thepolyol blend (90/10% by weight of high oleic soybean oil polyol andbranched poly(trimethylene ether) polyol), water, catalyst andsurfactant, and mixted for less than 10 seconds. The mixture is pouredinto a cup and is allowed to free rise. The foam is cured in an oven for15 minutes at 100° C.

Example 10

The foam is prepared as described in Example 9 except the polyol blendis a mixture of 10/90% by weight of high oleic soybean oil polyol andbranched poly(trimethylene ether) polyol.

TABLE 4 Example 9 Example 10 Component Parts by weight Parts by weightHigh Oleic Soybean Oil Polyol 90 10 Branched Polyol from Example 4 10 90Water 4 4 Silicon type surfactant 1 1 Potassium catalyst 2 2 Amine basedcatalyst 0.1 0.1 TDI index 105 105

The amount of TDI required is calculated based on the total hydroxylnumbers of polyols and water, and the Index of 105.

What is claimed is:
 1. A branched amorphous poly(trimethylene ether)polyol comprising repeating units of Formula I, Formula II, and FormulaIII

wherein R is methyl and Q is selected from Formula (IIIa) and (IIIb):

wherein m is 1-20 and n is 1 to 3, and further comprising end groups ofFormula IV, V, and VI:

and wherein the branched poly(trimethylene ether) polyol comprises therepeating units of Formula II and Formula III, together, from about 2.8mole % to about 10 mole %, and wherein the branched poly(trimethyleneether) polyol is amorphous.
 2. A composition comprising thepoly(trimethylene ether) polyol of claim 1 and at least one additiveselected from antioxidants and heat stabilizers.
 3. The branchedpoly(trimethylene ether) polyol of claim 1, having an equivalenthydroxyl functionality of about 2.1 to about 3.2 and a M_(n) of about250 to about
 6000. 4. The branched poly(trimethylene ether) polyol ofclaim 1 comprising pendant CH₂OH groups and chain end CH₂OH groups. 5.The branched poly(trimethylene ether) polyol of claim 1 wherein thepolyol is made from polycondensation of 1,3-propanediol and a triolcomonomer.
 6. A renewably sourced branched poly(trimethylene ether)polyol according to claim 1.